Fire spokesman Tom Piranio says Saturday that the 44-square-mile fire at the western end of the Santa Monica Mountains was started by an undetermined ignition of grass and debris on the side of U.S. 101. He says it's possible a piece of metal fell into the tinder-dry bush early Thursday, sparking an uphill fire that was quickly stoked by hot, windy weather.

The fire threatened thousands of homes as it marched to the coast, but only caused damage to just 15 homes.

Cool, moist air that returned to the region late Friday helped firefighters gain control of the blaze. It is 75 percent contained. Full containment was expected Monday, according to Ventura County fire officials.

The progress led authorities to lift all remaining evacuation orders.

"We've really transitioned from a fire attack to a mop-up patrol," Nick Schuler, battalion chief for the California Department of Forestry and Fire Protection, told the Ventura County Star.

One firefighter was injured in the Newbury Park area while battling the blaze and was taken to a hospital, the newspaper said.

The National Weather Service said an approaching low pressure system would bring showers in the evening and on Monday.

Nearly 2,000 firefighters using engines, bulldozers and aircraft worked to corral the blaze.

Firefighting efforts were focused on the fire's east side, rugged canyons that are a mix of public and private lands.

The change in the weather was also expected to bring gusty winds to some parts of Southern California, but well away from the fire area.

Despite its size and speed of growth, the fire that broke out Thursday and quickly moved through neighborhoods of Camarillo Springs and Thousand Oaks has caused damage to just 15 homes, though it has threatened thousands.